Nanoparticles Sampling inside the International Space Station

Nanoparticles were collected inside the International Space Station (ISS) with a thermophoretic sampler named Diapason (DTM Technologies, Modena, Italy), a device based on thermophoresis, a phenomenon whereby small particles suspended in a gas with a temperature gradient move towards the lower temperature region. Particles measuring from a few nanometers up to about 2 μm were deposited on transmission electron microscope grids and examined under a transmission electron microscope. The particles sampled were prevalently agglomerates of primary particles. Many of the aggregates examined were made up of multiple elements, prevalently Ca, Al, Si, K, Ca, Na, S, Ni and Ti. The preliminary results showed that the Diapason thermophoretic sampler works satisfactorily even in microgravity conditions and allows the measurement of ultrafine particles, which are the most dangerous for human health.